Table of Contents
What is the principle of operation of a relay?
Relay works on the principle of electromagnetic induction. When the electromagnet is applied with some current it induces a magnetic field around it.
What are the two operating principle of relay?
There are really only two fundamentally different operating principles: (1) electro- magnetic attraction, and (2) electromagnetic induction. Electromagnetic attraction relays operate by virtue of a plunger being drawn into a solenoid, or an armature being attracted to the poles of an electromagnet.
What is the principle of circuit breaker?
Working Principle of Circuit Breakers Under normal conditions – closed circuit – these contacts are touching each other, allowing the flow of electric current. These moving contacts are held together thanks to mechanical pressure exerted by another mechanism – a spring or compressed air, for example.
What is the output of relay?
Relay outputs are mechanical contacts and solid state outputs may take the form of transistor or TTL logic (DC) and triac (AC). Relay outputs are usually used to control up to 2 amps or when a very low resistance is required. Transistor outputs are open collector common emitter or emitter follower.
What is pin 30 on a relay?
Numbers of a Relay Note that each pin is numbered. 85 and 86 are the coil pins while 30, 87, and 87a are the switch pins. 87 and 87a are the two contacts to which 30 will connect. If the coil is not activated, 30 will always be connected to 87a. Think of this as the relay in the Normally Closed (OFF) position.
Is a relay analog or digital?
The Output may be digital, if that is the nature of the signal input, as digital signals are a subset of analog signals. To drive relay, output must be digital. (Necessary driver circuit required) . Relay have only mechanical contacts, whatever we want, can connected.
What is the basic principle of relay operation?
Basic Principle of Relay Operation. The Relay detects the abnormal condition by continuously monitoring electrical quantities which are different for healthy and faulty condition. The electrical quantities which may change during fault condition are voltage, current, frequency and phase angle.
What is a relay on a circuit breaker?
Definition: The relay is the device that open or closes the contacts to cause the operation of the other electric control. It detects the intolerable or undesirable condition with an assigned area and gives the commands to the circuit breaker to disconnect the affected area. Thus protects the system from damage.
What is an electromechanical relay?
Electromechanical relays transfer signals between its contact through a mechanical motion. It consists of two sections: the first is the electromagnet section and the other is the armature and mechanical contacts section. The electromagnet section consists of a set of coil wound over a magnetic core.
What happens when voltage is applied to a relay?
When voltage is applied to the coil, the contact shift from its original position to the other contact and returns to its previous position when the coil is de-energized. The above figure shows the most commonly used symbol of a relay. A1 and A2 represent its coil and 11, 12 & 14 represent its contacts. How to use relays in a circuit?